Methods:

Data on OHCAs in 1995-1997 and 2005-2008 were obtained from a prospective registry in the Netherlands. In addition, based on ICD interrogations in patients in North Holland, the number of OHCAs precipitated by VF/VT in 2005-2008 that were prevented by the ICD was estimated.

Results:

The annual incidence of OHCA caused by VF/VT decreased significantly by 3.7/100,000 inhabitants, from 21.1/100,000 in 1995-1997 to 17.4/100,000 in 2005-2008. In 2005-2008, ICDs prevented 81 cases of OHCA, corresponding to an annual decrease in incidence of 1.2/100,000 inhabitants.

Conclusions:

ICD therapy has accounted for approximately 33% of the decline in OHCA caused by VF/VT in the Netherlands.

Perspective:

The results of this study indicate that factors other than ICD therapy account for most of the reduction in the incidence of OHCA caused by VF/VT in the Netherlands. It should be noted that a delay in resuscitation or more rapid degeneration of VF/VT to asystole could result in asystole being the first documented arrhythmia in patients with OHCA that actually was precipitated by VF/VT. However, if the results of this study reflect a true reduction in the incidence of OHCA caused by VF/VT, in addition to ICD therapy, the more prevalent use of beta-blockers in patients with structural heart disease also could account for this.